New Horizons begins massive "treasure trove" data downlink

Image of a region near Pluto’s equator captured by New Horizons on July 14 reveals a range of youthful mountains(Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

When NASA's New Horizons probe made its historic flyby of Pluto on July 14, it gathered a wealth of information about the dwarf planet and its moons, but at a distance from Earth of over 3 billion mi (4.8 billion km), retrieving that data will take a very long time. To speed things up, NASA has begun an intensive download from the unmanned spacecraft that will return tens of gigabits of data over the next 12 months.

Until now, New Horizons has been concentrating on lower data-rate information from its energetic particle, solar wind, and space dust instruments with only a smattering of images thrown in as insurance against systems failures, but on September 5, NASA turned the metaphorical tap open. The probe is now sending back packets of information at a relatively high rate as it starts a download of high-resolution images and other data that will take about a year.

In an age of high-speed broadband, we're used to data streaming round the world in huge amounts at incredible speeds, but even seven weeks after its encounter with Pluto, the vast majority of the data recorded by New Horizons remains locked in its memory banks. This is because New Horizons, now speeding away from Pluto and out of the Solar System, is so far away that a radio signal takes 4.5 hours to reach Earth and with only a 12-watt transmitter, it can only manage 1 to 4 kilobits per second of data, depending on how the data is sent and which Deep Space Network antenna is receiving it.

NASA’s Deep Space Network of antenna stations used to receive the data from New Horizons(Credit: NASA)

"This is what we came for – these images, spectra, and other data types that are going to help us understand the origin and the evolution of the Pluto system for the first time," says New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado. "And what’s coming is not just the remaining 95 percent of the data that’s still aboard the spacecraft – it’s the best datasets, the highest-resolution images and spectra, the most important atmospheric datasets, and more. It’s a treasure trove."